Northrup, D. (1978). Trade without rulers: Pre-colonial economic development in south-eastern Nigeria. Clarendon Press.
芝加哥风格引文Northrup, David. Trade Without Rulers: Pre-colonial Economic Development in South-eastern Nigeria. Oxford: Clarendon Press, 1978.
MLA引文Northrup, David. Trade Without Rulers: Pre-colonial Economic Development in South-eastern Nigeria. Clarendon Press, 1978.
警告：这些引文格式不一定是100％准确.